Despite warnings about the lack of transparency, corruption scandals and companies with shaky financials, the Chinese stock market has leaped 300 percent in the past two years.

No other major market in the world has rewarded investors as generously. Consider: Brazil, Russia and India -- the other fast-growing countries that make up the so-called BRIC economies -- gained at most 170 percent over the same period. The Standard & Poor's 500-stock index rose 24 percent.

But like other emerging economies, China's poses some serious risks for investors. Its stock market is notoriously volatile. A series of one-day plunges have left the benchmark Shanghai composite index about 7 percent below its highs in May.

Concerned about speculation, the Chinese government is trying to temper the red-hot market. It is also trying to slow the rapid pace of economic growth, which could further cool the market. At the same time, Beijing is battling to limit fallout from tainted Chinese products sold in the United States.

A growing chorus of observers -- including U.S. analysts, Chinese officials and former Federal Reserve chairman Alan Greenspan -- are voicing concern that China's stock market is a bubble ready to pop. All this, while Wall Street is stepping up its offerings of China-focused investment products and as Chinese companies are going public on U.S. markets at a record pace.

So is it time to ease away from Chinese shares? Or has the great rise only just begun?

"There's a point where you have to revalue markets and stocks that have done so well so rapidly," said Kirk Brown, who oversees investing in foreign markets at American Beacon Advisors. While Brown doesn't expect Chinese stocks to fall sharply, he said they could be headed into a period "where they kind of languish for a number of quarters until earnings catch up to their stock prices. . . . I would think people would want to be more cautious in putting more money to work in China at this point."

Nonetheless, he and other money managers see reason to have exposure to China in the long run. They say the country's 1.3 billion people represent a consumer base whose potential has barely been tapped. The Chinese economy, projected to grow in the double-digits for the fifth straight year, is threatening to overtake Germany as the third-largest economy in the world.

"I think it ought to be clearer and clearer to people all the time that China's advance is real and that they probably would benefit to have some exposure to China," said Donald H. Straszheim, vice chairman at Roth Capital Partners and former chief economist at Merrill Lynch.

Investors should be aware, however, that it can be difficult to get trustworthy information about companies in China. Disclosure rules aren't up to global standards. Although the economy is opening up, it is still run by a communist government struggling to foster a free market. Many companies are state-owned.